题解 | #判断是不是平衡二叉树#

/*class TreeNode {
 *     val: number
 *     left: TreeNode | null
 *     right: TreeNode | null
 *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
 *         this.val = (val===undefined ? 0 : val)
 *         this.left = (left===undefined ? null : left)
 *         this.right = (right===undefined ? null : right)
 *     }
 * }
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param pRoot TreeNode类 
 * @return bool布尔型
 */
export function IsBalanced_Solution(pRoot: TreeNode): boolean {
    // write code here
    const getDepth = (node) => {
        if(!node) return 0
        let leftDepth = getDepth(node.left)    
        let rightDepth = getDepth(node.right)
        if(leftDepth === -1 || rightDepth === -1 || Math.abs(leftDepth - rightDepth) > 1) return -1
        return Math.max(leftDepth, rightDepth) + 1    
    }
    
    
    return getDepth(pRoot) !== -1
}